stage 1b cervical cancer treatmentstage 1b breast cancer prognosismalignant melanoma stage 1bmelanoma stage 1b prognosiscervical cancer 1bstage 1b breast cancer survival ratesstage 1b melanoma recurrence ratestage 1b melanoma survival ratestage 1b melanoma skin cancer1b melanoma prognosisstage 2b melanomastage 3b melanoma